/**
 * @license
 * Copyright (C) 2017 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
import '../base-url-behavior/base-url-behavior.js';

(function(window) {
  'use strict';

  const PROBE_PATH = '/Documentation/index.html';
  const DOCS_BASE_PATH = '/Documentation';

  let cachedPromise;

  window.Gerrit = window.Gerrit || {};

  /** @polymerBehavior Gerrit.DocsUrlBehavior */
  Gerrit.DocsUrlBehavior = [{

    /**
     * Get the docs base URL from either the server config or by probing.
     *
     * @param {Object} config The server config.
     * @param {!Object} restApi A REST API instance
     * @return {!Promise<string>} A promise that resolves with the docs base
     *     URL.
     */
    getDocsBaseUrl(config, restApi) {
      if (!cachedPromise) {
        cachedPromise = new Promise(resolve => {
          if (config && config.gerrit && config.gerrit.doc_url) {
            resolve(config.gerrit.doc_url);
          } else {
            restApi.probePath(this.getBaseUrl() + PROBE_PATH).then(ok => {
              resolve(ok ? (this.getBaseUrl() + DOCS_BASE_PATH) : null);
            });
          }
        });
      }
      return cachedPromise;
    },

    /** For testing only. */
    _clearDocsBaseUrlCache() {
      cachedPromise = undefined;
    },
  },
  Gerrit.BaseUrlBehavior,
  ];

  // eslint-disable-next-line no-unused-vars
  function defineEmptyMixin() {
    // This is a temporary function.
    // Polymer linter doesn't process correctly the following code:
    // class MyElement extends Polymer.mixinBehaviors([legacyBehaviors], ...) {...}
    // To workaround this issue, the mock mixin is declared in this method.
    // In the following changes, legacy behaviors will be converted to mixins.

    /**
     * @polymer
     * @mixinFunction
     */
    Gerrit.DocsUrlMixin = base =>
      class extends base {
      };
  }
})(window);
